Axisymmetric analytical rigid: multiple surfaces?

I have a simple model - an axisymmetric analytical rigid body, with the shape of a rectangular.

 

I'd like to assign different friction coefficients to different edges on the rectangular. However, when I select surfaces, all the edges are always connected to be one surface. Is there a way to break it into multiple surfaces, constituted of different edges?

 

Thank you!

 

Shawn